(1) Field of the Invention
This invention relates generally to the field of semiconductor integrated circuit (IC) devices for driving a load and more particularly, to a semiconductor integrated circuit device with isolation structures to allow the application and processing of mixed signals to drive loads and a method for fabricating the same.
(2) Description of Related Art
Most Alternative Current (AC) to Direct Current (DC) converter circuits convert a high voltage AC input signal to a low voltage AC by using a transformer that steps down the incoming high voltage AC signal, and then convert the low voltage AC to low voltage DC using full-wave bridge rectifiers. Regrettably, most prior art AC to DC converters are bulky and in fact, may be larger than the loads to which they are connected due to the use of transformers. The use of transformers is one reason that conventional IC semiconductor manufacturing techniques cannot be used to integrate the converter circuits into a single IC chip to provide a compact and less bulky converter.
Another limiting factor with respect to conventional IC fabrication techniques and the end-product IC chip package is that converters are generally considered high voltage devices wherein high voltage (incoming AC) is processed and a low voltage (outgoing DC) signal is output. However, most IC chips operate on a single low signal power (e.g., 3.5 or 5 volts). The same IC chip would have to simultaneously process an incoming high voltage AC signal and convert it to a low DC signal, while at the same time use a low voltage signal (e.g., 3.5 or 5 volts) for its own operation and control, none of which is possible with conventional ICs and IC fabrication techniques.
Accordingly, in light of the current state of the art and the drawbacks to current AC to DC converters mentioned above, a need exists for a high voltage AC to low voltage DC converter for driving a load that would be fabricated on a single IC chip, that would reduce bulk, and that would operate efficiently without much generation and dissipation of heat.